Rapidly operating machines must often be stopped in a short time on special occasions, such as breakdowns or interruptions in the working process. This is necessary for instance in looms, when irregularities such as a thread breakage or untimely flight of the shuttle occur during the weaving process, so that no greater damage occurs to the material being woven, for example, but the shuttle being struck in the shed. This requires very efficient brakes and release devices for the braking process, which respond with as little delay as possible to the interference signals transmitted by monitoring members. Transmission of the interference signals from the monitoring members to the release device usually takes place electrically, wherein release is provided by an electromagnet unlocking an actuating linkage for a braking member (brake shoe, brake band or the like), which is normally held under the action of force by a lock and when the brake is released, is held by the magnetic core moved by the magnetic force.
A device of this type is known in which the actuating linkage of the brake comprises a sleeve and a rod which fits in the latter axially displaceably, wherein one of these parts is rigidly connected to the machine frame and the other to the braking member. When the brake is released, the parts are telescoped together against spring tension and held in this position by a bolt passed through perpendicularly. For unlocking, the bolt is withdrawn from the locking position by means of an electromagnet and braking is initiated by the spring tension which biasses sleeve and rod apart.
This arrangement has the disadvantage that, on withdrawal of the locking bolt, considerable friction forces and in addition a considerable distance corresponding to the sleeve diameter must be overcome, which delays release.
It is the object of the invention to create a release device of the kind mentioned above in which release is accelerated.